The subject disclosure generally relates to electric tools, and more specifically, to an electric tool for outputting torque.
Electric tools for outputting torque include two types: one type is for continuously transmitting torque and the other type is for outputting torque in an intermittent impact manner, wherein a typical electric tool among the latter type is an impact wrench. In the impact wrench, there is one type comprising a mechanism for achieving a circumferential impact by using a centrifugal force. By using a centrifugal force generated upon high-speed rotation, an impact hammer is enabled to swing about a metal pin against the action of a spring latch so as to impact with an output shaft. Such a product is advantageous in that the impact torque is associated with a rotation speed of a base when the impact hammer swings, and in that when a pre-pressure of the spring latch is very large, the rotation speed of the base is very high so that the impact action occurs and a very large impact torque can be generated. A drawback of such a product lies in that once the pre-pressure of the spring latch is preset, the machine will always impact at a certain speed that the user cannot adjust. In the case that a small torque is needed, the workpiece to be fixed might be damaged by using this machine.